FIELD OF THE INVENTION
The invention relates to a bus driver for driving a signal on a bus line which is capacitively coupled to at least one further bus line having further signals.
Capacitive coupling of neighboring bus lines frequently occurs during the operation of a bus. The capacitive coupling is undesirable and, in the worst case, can lead to interference with, and thus to alteration of, the signals driven on the bus lines. The worst case of capacitive coupling occurs when a signal on a neighboring bus line has an opposite timing edge to the signal to be driven. Owing to the undesirable capacitive coupling that may be expected, the signal to be driven must be amplified and thus adapted to the worst case of capacitive coupling. However, the amplification leads to unnecessarily fast timing edges of the signal to be driven. The fast timing edges are likewise undesirable, however, since they cause electromagnetic radiation, whereby neighboring components can be influenced in an interfering manner. In order to reduce the electromagnetic radiation and, consequently, in order to improve the electromagnetic compatibility (EMC), it is necessary, therefore to take measures for adaptation to the respective capacitive coupling of the bus lines.
To date, bus drivers of the generic type have typically been adapted to the worst case in the event of capacitive coupling with neighboring bus lines, that is to say to the case described above, when opposite timing edges occur on neighboring bus lines. However, this very rigid dimensioning, adapted to the worst case of capacitive coupling, is frequently not satisfactory either, since excessively great compensation takes place in the region outside the extreme case described above and excessively steep, fast timing edges are consequently produced. As a result, the electromagnetic radiation is maximized.